Helminthiasis

Helminthiasis (helminthic infestation): causes, symptoms, diagnosis and treatment methods.

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Helminthiases are diseases of humans, animals and plants caused by parasitic worms (helminths).

Causes of helminthiasis

Currently, more than 70 species of the 250 known helminths that parasitize the human body are found in our country.The most common are roundworms (roundworms, pinworms, trichinella, whipworms), tapeworms (pork, cattle and dwarf tapeworms, broad tapeworm, echinococcus) and flukes (liver and cat flukes).

Helminths are characterized by stages of development: eggs → larvae → sexually mature forms.

Infection with helminths most often occurs after their eggs and/or larvae enter the body.Depending on the mechanism of infection and transmission routes, helminthiases are divided into: geohelminthiases, biohelminthiases and contact helminthiases.Geohelminths develop without intermediate hosts, biohelminths develop with a sequential change of one, two or three hosts, contact helminths are transmitted by contact.

Pork tapeworm, bovine tapeworm, echinococcus and other types of worms develop with a successive change of one, two or three hosts.Intermediate hosts can be fish, molluscs, crustaceans and insects.A person becomes infected with these helminths by eating food that has not undergone full heat treatment:

• beef infected with bovine tapeworm larvae;
• pork affected by Finnish pork tapeworm;
• lightly salted and raw fish with larvae of opisthorchis or broad tapeworm;
• raw water or vegetables and fruits treated with this water.

Whipworms, roundworms, hookworms and necators thrive without intermediate hosts.The eggs and larvae of these pests enter the soil along with feces.If personal hygiene rules are not followed, they enter the body of a new host.

Through contact - that is, through personal contact between a healthy person and an infected person, through the use of shared utensils, toiletries, linen and through inhalation of dust in a room where an infected person is - enterobiosis (pathogen - pinworm) and hymenolepiasis (pathogen - dwarf tapeworm) are transmitted.In the case of enterobiosis, autoinfection often occurs.

Helminths of a certain type parasitize certain organs, causing various helminthiases:

• in the large intestine - pork, cattle, dwarf tapeworms, nematodes (hookworms, roundworms, strongyloides), pinworms, whipworms.From the intestinal lumen, pork tapeworm larvae can enter the bloodstream and spread throughout the body, settling in fatty tissues, muscle vessels, eye chambers and the brain;
• in the liver and bile ducts - trematodes (opisthorchis, clonorchis, fasciola).Echinococcal cysts are mainly localized in the liver, and after their rupture, daughter blisters can be found in the mesentery, peritoneal layers, spleen and other organs;
• in respiratory organs - echinococci, alveococci, pulmonary flukes, causing paragonimiasis;
• in the nervous system - schistosomiasis, paragonimiasis, echinococcosis and alveococcosis;
• in the organs of vision - oncocercosis, loiasis, complicated forms of taeniasis;
• in the circulatory system - necatorosis, schistosomiasis, diphyllobothriasis;
• in the lymphatic system - filariasis, trichinosis;
• in the skin and subcutaneous tissues - hookworm, oncocercosis, loiasis, larval stage of schistosomiasis;
• in the skeletal system - echinococcosis;
• in skeletal muscles - trichinosis, cysticercosis of muscle tissue.

The lifespan of helminths in the body of the definitive host can be different, depends on the type of parasite and varies from several weeks (pinworms) to several years (tapeworm) and decades (fasciola).

Disease classification

There are two types of worms that parasitize humans:

• Nemathelminthes – roundworms, class Nematoda;
• Platyhelminths are flatworms, which include the classes Cestoidea - tapeworms, Trematoda - the class flukes.

Depending on the routes of propagation of parasites and the characteristics of their biology, they are distinguished:

• biohelminthiases;
• geohelminthiasis;
• contact helminth infections.

Symptoms of helminthiasis

Helminths have different effects on the human body:

• antigenic effects, when local and general allergic reactions develop;
• toxic effect (helminth waste products cause discomfort, weakness, dyspeptic symptoms);
• traumatic effect (when parasites are attached to the intestinal wall, blood supply is disrupted with necrosis and subsequent atrophy of the mucous membrane; absorption processes may be disrupted; mechanical compression of tissues by helminths);
• secondary inflammation resulting from the entry of bacteria following the migration of helminth larvae;
• violation of metabolic processes;
• as a result of absorption of some helminths into the blood, anemia occurs;
• neuro-reflex effect - irritation of nerve endings by helminths causes bronchospasm, intestinal dysfunction, etc.
• psychogenic effect, manifested by neurotic conditions, sleep disturbances;
• immunosuppressive effect.

Helminthiases are characterized by stages of development.Each stage is characterized by its own clinical symptoms.

At the initial acute stage, helminths most often do not release eggs yet, sensitization of the body occurs (production of antibodies, release of inflammatory mediators, increased permeability of the vascular wall) and traumatization of the organs through which the larvae migrate.Clinical symptoms may be absent, but in some cases the disease may occur with pronounced clinical manifestations.The acute phase lasts 1 to 4 months, sometimes 8 to 10 months or more.

Patient complaints in the acute stage:

• increase in temperature from several days to two months (mild fever or above 38 ° C, accompanied by chills, severe weakness and sweating);
• recurrent itchy rashes;
• local or generalized edema;
• enlarged regional lymph nodes;
• pain in muscles and joints;
• cough, asthma attacks, chest pain, prolonged catarrhal symptoms, bronchitis, tracheitis, pneumonia-like symptoms, asthmatic syndrome, hemoptysis;
• abdominal pain, nausea, vomiting, stool disturbances.

At the end of this stage of helminthic infections, acute allergic phenomena gradually subside and the clinic of the chronic stage has not yet had time to develop.

The acute stage becomes subacute when the “young” helminths gradually mature.Then comes the chronic stage, corresponding to the evolution of parasites into sexually mature individuals.The clinical picture develops against the background of the toxic effect of helminth waste, the traumatic effect of helminths on organs (hookworm, trichuriasis, etc.), mechanical effects (an echinococcal cyst develops in the liver, compresses neighboring organs; cysticerci - in the brain), a secondary inflammatory process (duodenitis is observed in strongyloidiasis), metabolic disorders(hypo- or avitaminosis), functional disorders of the stomach and duodenum, secondary immune deficiencies, etc.

The symptoms depend on the organs in which the helminths parasitize, their size and quantity.

Forintestinal helminthiasisThe following syndromes are characteristic:

• dyspeptic (stomach discomfort, feeling of fullness after eating, early satiety, bloating, nausea);
• painful;
• asthenoneurotic (feeling of extreme fatigue, increased nervous excitability and irritability).

Enterobiasis is characterized by nighttime perianal itching.In case of massive infestation with roundworms, there may be intestinal obstruction, pancreatitis, obstructive jaundice.

Intestinal cestodoses(taeniarinhoz, diphyllobothriasis, hymenolepiasis, taeniasis and others) are asymptomatic or have a small number of symptoms (with symptoms of dyspepsia, pain, anemia).

Liver trematodes(fascioliasis, opisthorchiasis, clonorchiasis) cause:

• chronic pancreatitis;
• hepatitis;
• cholecystocholangitis;
• neurological disorders.

Hookwormmanifests as an asthenovegetative syndrome (weakness, fatigue, pale skin) due to the development of iron deficiency anemia.

Filariasis is characterized by an allergic syndrome of varying severity and regional lymphadenitis.

Urogenital schistosomiasismanifests itself by the appearance of blood at the very end of urination, frequent urge to urinate, pain during urination.

Alveococcosis, cysticercosis, echinococcosiscan remain asymptomatic for a long time.At a later stage, suppuration or rupture of cysts containing parasites leads to anaphylactic shock, peritonitis, pleurisy and other serious consequences.

For diseases caused by parasitism of migratory larvaezoohelminthswhen a person is not the natural host, distinguish between cutaneous and visceral forms.The cutaneous form is caused by the penetration of certain animal helminths under human skin: schistosomatids of waterbirds (trematodes), hookworms of dogs and cats, strongyles (nematodes).When a person comes into contact with soil or water, helminth larvae penetrate the skin.There is a burning, tingling or itching sensation at the site of helminth introduction.There may be a short-term fever and signs of general malaise.After 1-2 weeks (less often 5-6 weeks), recovery occurs.

The visceral form develops as a result of ingestion of helminth eggs with water and food.At the beginning of the disease, there may be discomfort, allergic exanthema (rash).In the human intestine, larvae hatch from helminth eggs, penetrate through the intestinal wall into the blood, reach the internal organs, where they develop and reach 5-10 cm in diameter, compress the tissues and disrupt the functioning of organs.When tapeworm larvae (cysticerci, tsenura) are localized in the membranes and substance of the brain, headaches, signs of cerebral hypertension, paresis and paralysis, as well as epileptiform convulsions are observed.Larvae can also be located in the spinal cord, eyeball, serous membranes, intermuscular connective tissue, etc.

The result of helminthiasis can be complete cure with the elimination of helminths or the development of irreversible changes in the host's body.

Diagnosis of helminthiasis

The diagnosis of helminthiasis is established on the basis of a combination of complaints, information received from the patient about the course of the disease, data from laboratory and instrumental examination methods.

In the acute phase of helminth infections, there is a blood reaction to the presence of a helminth in the body, therefore the following studies are recommended:

• clinical blood test: general analysis, leukoformula, ESR (with microscopy of a blood smear in the presence of pathological changes);
• biochemical blood test:
• total proteins, albumin, protein fractions; 
• assessment of renal function indicators (urea, creatinine, glomerular filtration);
• assessment of liver function indicators (bilirubin, ALT, AST, alkaline phosphatase);
• pancreatic alpha-amylase;
• evaluation of carbohydrate metabolism: glucose (in the blood), glucose tolerance test with measurement of glucose in venous blood fasting and after exercise after 2 hours.

The following biological materials can be examined for the presence of helminths: feces, blood, urine, duodenal contents, bile, sputum, muscle tissue, rectal and perianal mucus.

Since helminths are not excreted in the feces at any stage of their development, it is recommended to give stools three times - every 3-4 days.

• Analysis of feces for helminth eggs.
• Enterobiasis test (pinworm eggs), swab.
• Microscopic examination of stools for eggs of the enterobiasis pathogen Enterobius vermicularis (pinworms).
• Enterobiasis test (pinworm eggs), spatula.
• The analysis is necessary if there is a suspicion of pinworm infection, as well as during hospitalization and registration of a medical record.
• Analyzes for kindergarten and school.

The examination program for children is intended to be completed before entering kindergarten or school.The results of these studies are necessary to obtain a medical certificate in accordance with the 026U form approved by the Ministry of Health of the Russian Federation.

Carrying out immunological studies - determination of specific antibodies against helminths:

• roundworm IgG antibodies;
• Anti-echinococcus IgG;
• IgG antibodies against Toxocar antigens;
• Anti-Opisthorchis felineus IgG (IgG class antibodies against cat fluke antigens);
• IgG antibodies against Trichinella antigens;
• antibodies against the causative agent of anisakiasis (nematodes of the genus Anisakis), IgG;
• antibodies to the causative agent of clonorchiasis, IgG;
• Antibodies against Strongyloides stercoralis, the causative agent of strongyloidiasis, IgG.

A test aimed at detecting IgG antibodies to the causative agent of angulosis is used for early serological diagnosis of angulosis in cases of clinical suspicion (eosinophilia, serpentine skin lesions, pulmonary or gastrointestinal symptoms) of this disease.

In difficult cases, the following studies may be recommended:

• Plain x-ray of the thoracic organs;
• complete ultrasound examination of the abdominal organs (liver, gallbladder, pancreas, spleen);
• Computed tomography of the abdominal cavity and retroperitoneum;
• CT scan of the chest and mediastinum;
• Brain and skull scan.

Which doctors should I contact?

If you suspect helminthiasis, you should consult a therapist or general practitioner, and together with your child, consult a pediatrician.

If there are indications for surgical treatment, the patient is referred to a surgeon.

Treatment of helminthiasis

Most people with helminths do not need to be hospitalized.Patients with tissue helminthiasis, regardless of its severity, and patients with a severe and complicated course of the disease are treated in the hospital.

Treatment is carried out with anthelmintic drugs.The frequency of administration and dosage of the drug depend on the age and body weight of the patient and are established by the doctor.

Desensitization therapy, detoxification and vitamin therapy may be indicated.To reduce the temperature, nonsteroidal anti-inflammatory drugs are prescribed, for an allergic reaction and itching - antihistamines, for severe edema - diuretics.In severe cases, hormonal medications are necessary.

The presence of helminths in organs and tissues may be an indication for surgical treatment.

Complications

• Bronchial asthma.
• Pneumonia.
• Bowel cancer.
• Cirrhosis.
• Portal hypertension.
• Gastrointestinal bleeding.
• Ascites.
• Hepatitis.
• Liver abscess.
• Peritonitis.
• Allergic myocarditis.
• Meningoencephalitis.
• Chronic glomerulonephritis.
• Chronic kidney disease.
• Hemostasis disorders.
• Loss of vision.

Helminthiasis prevention

Preventive measures aimed at preventing helminth infection include:

• compliance with personal hygiene rules (use of an individual towel, personal hygiene items and other daily use accessories);
• use only high-quality water in daily life;
• regular vaccination and deworming of pets;
• Thorough washing of vegetables, fruits and berries before consumption;
• sufficient heat treatment of meat and fish products.

With regular contact with pets, children in children's groups, contact with land, fishing or hunting hobbies, frequent trips to exotic countries, prevention can be achieved through the use of medications.Drug prophylaxis should be taken by the whole family twice a year (for example in spring and autumn).

IMPORTANT!

The information in this section cannot be used for self-diagnosis and self-treatment.In case of pain or other exacerbation of the disease, diagnostic tests should be prescribed only by the attending physician.To make a diagnosis and correctly prescribe treatment, you must contact your doctor.